A cracked toilet tank may be a sign of a necessary replacement or a sign of a much needed repair to your current tank. An unattended crack in a toilet tank just continues to grow until it starts to leak. These kinds of cracks may happen because of a number of factors, depending on the type of water tank you have on your toilet. Your toilet's tank operates by retaining water that you use during a flush and refilling it after you finish the flushing process on your toilet bowl.
Your toilet tank simply grows old after a period of time and starts developing some cracks in the porcelain. You might have an older tank made with a mixture of cement, causing the tank to get several cracks inside and outside it, especially if you have a major difference in temperature between the water inside the tank and the air outside. If you have an old tank that has cracks branching out from one point because of age, you'd best buy a new one instead of trying to fare with the older tank.
Repairs or Adjustments
Any kind of repair performed on your toilet's tank might break a small piece of the tank because of the porcelain's delicacy. This kind of damage results from carelessness in handling the unit while making some kind of adjustment. While tightening bolts around the tank, you might end up cracking it if you make the bolts too tight. While placing the lid back onto your tank after doing an interior repair, take care not to set it down too hard or the porcelain cracks slightly at the top. These cracks may extend and later damage the entire tank.
Even small accidents, like dropping something light onto the tank lid, can cause the weight from the lid to push down onto the tank, causing pressure to build up and eventually cracking the top of the tank. If you fall from the shower, and use the tank to break your fall, the same is more than likely to happen as well because of pressure. Handle your toilet's tank with extreme and delicate care as you would with an ornament. If the tank springs a leak, turn off the water supply to the tank and replace it as soon as you can. You may still use the tank if you chipped off some of the top and the water doesn't leak, but you still must replace it as soon as possible.